Multiplying fractions is not NEARLY as hard as adding or subtracting them! In fact, if you know your times tables, you will be fine. In order to multiply fractions, you do NOT need common denominators! You simply set up the multiplication problem, like this:
..........................................................................1/2 x 1/4
Then you multiply the numerators, and the denominators get multiplied together. In this case, you would be multiplying ....................................... 1 x 1 (the numerators) and 2 x 4 (the denominators).
When complete, it will look like this: .......................................................................... 1/2 x 1/4 = 1/8 Once you get your answer, make sure it is simplified (if you can reduce it, do so if not, leave it the way it is). Then, you’re done!
Dividing fractions (fraction division) is almost exactly like multiplying fractions. There is only one small step you have to do first …................................................................FLIP! In order to divide fractions, you must flip (or invert) your second fraction. Taking the inverse of the second fraction means that you put the number that is the numerator on the bottom, and the number that is the denominator on the top.
You must leave the first fraction alone, do not do anything to it. You ONLY flip the second fraction. A flip (inversion) would look like this: …...............................................................1/2 becomes 2/1
See? The numerator got moved to the bottom, and the denominator got moved to the top. Once you have flipped, then you multiply the two fractions together. One common phrase to help you remember how to divide fractions is: ...............................................................,,,,,,,,.......“Flip and multiply!”
Let’s try this in a fraction division problem. Here’s an example ................................................................................... 3/4 / 1/2
Remember, we’re going to flip the second fraction, and then multiply. Here’s what it looks like after we flip and change our division sign to multiplication: .....................................................................................3/4 / 2/1
We multiply the numerators (3 x 2) and the denominators (4 x 1) and get…
Normally we would stop here, but in this example, we have an improper fraction. After you convert this fraction into a mixed number you will get 1 2/4, and make sure it’s simplified to 1 1/2, and you’re done!
NOTE: two numbers are reciprocals of each other when their product is 1. (when you multiply 2 numbers together, the result is called a product) Reciprocals can be represented as: ..............................................................................a/b and b/a reciprocal to each other. Click on the link below to test your reciprocal skills http://au.ixl.com/math/year-7/reciprocals click on the link below to sing along and remember dividing fractions! http://www.youtube.com/watch?v=OGUaN-F80NA
Multiply Fractions
Multiplying fractions is not NEARLY as hard as adding or subtracting them!
In fact, if you know your times tables, you will be fine.
In order to multiply fractions, you do NOT need common denominators! You simply set up the multiplication problem, like this:
.......................................................................... 1/2 x 1/4
Then you multiply the numerators, and the denominators get multiplied together. In this case, you would be multiplying
....................................... 1 x 1 (the numerators) and 2 x 4 (the denominators).
When complete, it will look like this:
.......................................................................... 1/2 x 1/4 = 1/8
Once you get your answer, make sure it is simplified (if you can reduce it, do so if not, leave it the way it is).
Then, you’re done!
Click here very important! I will go through it on the board as a class also!
http://www.youtube.com/watch?v=m-lwRcHFxGI&feature=plcp&context=C3a40eceUDOEgsToPDskJWOOrRemvjgC8HVQ9eLJ4I
Click below for Multiplying fraction word problems
http://au.ixl.com/math/year-7/multiply-fractions-word-problems
Click on the link below for more Multiplying fractions!
http://au.ixl.com/math/year-7/multiply-fractions
Divide Fractions
Dividing fractions (fraction division) is almost exactly like multiplying fractions. There is only one small step you have to do first …................................................................ FLIP!
In order to divide fractions, you must flip (or invert) your second fraction.
Taking the inverse of the second fraction means that you put the number that is the numerator on the bottom, and the number that is the denominator on the top.
You must leave the first fraction alone, do not do anything to it. You ONLY flip the second fraction. A flip (inversion) would look like this:
…...............................................................1/2 becomes 2/1
See? The numerator got moved to the bottom, and the denominator got moved to the top.
Once you have flipped, then you multiply the two fractions together. One common phrase to help you remember how to divide fractions is:
...............................................................,,,,,,,,.......“Flip and multiply!”
Let’s try this in a fraction division problem. Here’s an example
................................................................................... 3/4 / 1/2
Remember, we’re going to flip the second fraction, and then multiply. Here’s what it looks like after we flip and change our division sign to multiplication:
.....................................................................................3/4 / 2/1
We multiply the numerators (3 x 2) and the denominators (4 x 1) and get…
..........................................................................................6/4
Normally we would stop here, but in this example, we have an improper fraction.
After you convert this fraction into a mixed number you will get 1 2/4, and make sure it’s simplified to 1 1/2, and you’re done!
NOTE: two numbers are reciprocals of each other when their product is 1. (when you multiply 2 numbers together, the result is called a product) Reciprocals can be represented as:
..............................................................................a/b and b/a reciprocal to each other.
Click on the link below to test your reciprocal skills
http://au.ixl.com/math/year-7/reciprocals
click on the link below to sing along and remember dividing fractions!
http://www.youtube.com/watch?v=OGUaN-F80NA
Click the link below for an awesome game of soccer!
http://www.funbrain.com/cgi-bin/fract.cgi?A1=s&A2=10&A15=1
Click on the link below to answer some real question! ;)
http://au.ixl.com/math/year-7/divide-fractions-word-problems
Click on the link below to see Division with models/diagrams
http://au.ixl.com/math/year-7/divide-by-fractions-with-models